A prospective study of sensory function in patients with type 2 diabetes

Sensory function was prospectively examined in 201 Type 2 diabetic patients over a 2-year period. Quantitative sensory testing for vibration, cool, warm, and pressure perception at the hallux was performed at baseline, 1-month, 1-year, and 2-year visits. There were statistically significant increments of thresholds for all sensory modalities from the baseline visit to the 1-year visit (p < 0.001) and from the 1-year visit to the 2-year visit (p < 0.001). Thirty percent of 77 subjects considered to be at low risk for foot ulceration at baseline progressed to a higher risk category at the 2-year visit. There were no significant differences in mean glycosylated haemoglobin, height, sex distribution, age, or diabetes duration when patients who had a faster progression of insensitivity were compared with patients who had a slower progression. There was a high degree of autocorrelation between baseline and 2-year visits for all sensory modalities (r = 0.83 to r = 0.88, p < 0.001 for all). Also, changes in sensory thresholds from the baseline to 2-year visits for one modality tended to correlate with other modalities (r = 0.36 to r = 0.70, p < 0.001 for all). These data indicate that an appreciable proportion of Type 2 diabetic patients are at risk for a marked rate of decline of sensory function, and suggest a need for at least yearly quantitative sensory testing.